Piano



Dec` ll, 1928. 1,694,789

F. s. MUKEY PIANO Filed April l5. 1919 4 Sheets-Sheet l-llllllllllllllllIllllllillll @www 20% 52%M QM atto-maui Sly-... mm

u vento/c F. S. MUCKEY Dec. ll, 1928.

PIANO Filed April 15. 1919 4 Sheets-Sheet 2 F. S. MUCKEY PIANO FiledApril l5. 1919 4 Sheets-Sheet 3 Dec. 11, 1928.

Dec. ll, 1928. 1,694,789

F. s. MUCKEY PIANO Filed April 15. 1919 4 sheets-sheet 4 T5231?m'rarnrhfffff Patented Dec. l1, 1928.

UNITED `STATES .1,694,189 PATENT OFFICE.

FLOYD S. MUCXEY, OF NEW YORK, N. Y., ASSIGNOB, BY DIRECT AND MESNEASSIGN- MENTS, OF ONE-TENTH TO JOSEPH F. OBRIEN, OF WEST NEW YORK, NEWJERSEY; THREE-'LENTES TO JOSEPH W. GOODWIN, 0F RICHMOND HILL, NEW YORK;AND SIX-TENTHS T MUCKEY PATENTS CORPORATION, A CORPORATION OF NEW YOBK.

PIANO.

Application led April 15,1919. Serial No. 290,189.

This invention relates to improvements in ianos.

ere are` three prerequisites to obtaining the best tone quality in anymusical instrument, namely: (l) the fundamental of each composite toneproduced should at all times have greater intensity than any otherpartial tone of the composite tone, (2) the partial tones of eachcomposite tone should gradually diminish in intensity as they rise inseries from the fundamental, and (3) all the partial tones of eac-hcomposite tone should continue without any intermittence and with thesame relative intensity to one another during the interval that, theycomposite tone continues to be heard. In many, if not all, of thecomposite tones heretofore produced by the sounding boards of pianos thefundamental does not at all times have greater intensity than any otherpartial tone of the composite tone, and the fundamental and otherpartial tones of the composite tone` do not continue with the samerelative intcnsit-y to one another during the interval that thecomposite tone continues to be heard, `but on the contrary thefundamental diminishes in intensity and dies out much more quickly thanthe overtones. This is particularly noticeable in the middle andv theupper part of the scale. Furthermore, the fundamental as well as each ofthe other partial tones, at certain periods, either stops entirely for ashort time or is much weaker in intensity.

It is, of course, desirable to approach this best tone qualityhereinabove defined as closely as possible, and theprincipal objects ofmy invention are (l) to produce a piano in which the strings willoriginate and the sounding board reproduce composite tones in which thelow partial tones viz, the fundamental and first overtone will, at alltimes, have greater intensity than any other partial tone of thecomposite tone, (2) to produce such tones inwhich the partial tonesgradually diminish in intensity as they rise in series from thefundamental or first overtone, and (3) to produce such composite tonesin which the partial tones continue in regular and unbroken periodicsequence during the interval that the composite tone continues to beheard and Without any intermittence in the relative intensity of thesound waves comp-rising the tone. Tones having some or all of suchcharacteristics will be of more pleasing quality.

Another obj ect of my invention is to ca-use the production of alsounding board which will be sufficiently sensitive to proportionatelyand with substantial accuracy reproduce substantially all the vibrationsthat are transmitted to it from the strings through the bridges. Such asounding board should be sufiiciently thin to accurately respond to thefundamental and first overtone which I shall hereinafter call lowpartial tones; it should be of substantially uniform thickness andwithout ribs and should also be of substantially counterpoised texture.A board having these characteristics is more responsive' to such lowpartial tones than the sounding boards heretofore employed as thevarious elements common to other sounding boards and which areeliminated, cause interference with responsivenessto and roduction ofthe low partial tones. Suc a sounding v board will reenforce compositetones having the low partial tones of relatlvely stronger intensity thanany of the higher overtones and I shall hereinafter term such asensitive board as a predominant low partial tone sounding board and aboard which is not so sensitive as a predominant higher overtonesounding board.

In the preferred embodiment of my invention I employ such a predominantlow partial tone sounding board in combination with a support consistingof sound-posts and a secondary sounding board spaced from the primaryboard and connected thereto by such sound posts.

Another object of my invention is to provide between the primary andsecondary sounding boards a resonance cavity of a shape which willconcentrate and further reinforce the tones produced by the adjacentsides of the board and particularly the fundamental and lower overtonesof the composite tones.

Another object of my invention is to so position the sound posts betweenthe boards as to cause such sound posts to cause that portion of thesound board between the lridge and the connection of such board to theframe at the opposite side of the osts to act as a lever in thetransmission o vibrations from the primary board to the secondary boardand in the transmission -back .to the primary board of the res ondingimpulse caused by the resilience o the secondary board.

In the accompanying drawings like characters of reference denotecorresponding parts throughout all the views. of which Fig. l is avertical transverse section of a piano embodying my invention;

Fic. 2 is a front elevation of a primary Asoun ing board with astring-supporting plate and strings mounted adjacent thereto and showingin dotted lines the positions of the sound posts, and frame uprights andthe shape of the resonance cavity;

Fig. 3 is an elevation with the back removed and part of the framemembers being shown in section;

Fig. 4 is a section on the line 4-4 of Fig. 3;

Fig. 5 is a vertical section through the sounding board of my piano.

Fig. 6 is a view in plan of a sound board preferably employed by me, apart of the top layer being broken away to show the cross graining ofthe two layers Fig. 7 is an enlarged view of the upper corner of amodified form of sounding board and a modified bridge for the hightreble strings;

Fig. 8 is a section on the line 8-8 of Fig. 7

Fig. 9 is an enlarged section on the line 9-9 of Fig. 3.

Referring now to these drawings, my invention is here shown applied toan upright piano but, by suitable modifications in the frame and otherparts, may be applied to grand pianos or other types. In these drawings,1 indicates a primary sounding board mounted at one side of a framecomprising end uprifrhts 2 and 3; intermediate u rights 4, 5, an 6 andwrest plank 7 and ottom beam 8. Said primary sounding board compriseswhat I shall term a predominant low partial tone board by which term Idesire to include all boards or sounding elements which are adapted tosegment favorably for the product-ion or reinforcement of compositetones in which the fundamental or the first overtone predominates withthe higher overtones diminished in intensity in contradistinction toboards or elements which segment favorably for the production ofcomposite tones having a predominance of higher overtones.

Such a sensitive sounding board must bo comparatively thin and thedegree of thinness is determined by the requirement that the soundingboard must also be rigid enough to retain its proper position whensubjected to the pressure of the strings upon the bridges and to reactquickly to the impulses it receives.

Practice has shown that boards of spruce 14 such as usually employed ofappreciably over one-half inch in thickness segment favorably for theproduction of tones having a redominance of higher overtones, and mayliie called predomlnant overtone boards while boards of such wood of lessthickness segment favorably for the production of com site tones havinga predominance of fun amental or the first overtone and may be thuscalled predominant low partial tone boards.

Applicant employs a predominant low partial tone sounding board which isnot reinforced by ribs attached to it. I have built up a sounding boardless than the required onehalf an inch in thickness from lammations orsuperposed layers of spruce Wood having the grains of each layercrossing each other at pro er angles, that is if two layers, 60% if)three layers, etc., and have crowned the same at the time of securingsuch laminations together. This produces a board which is sufficientlysensitive to accurately and proportionately reproduce all the partialtones, especially the lower partial tones, and is substantiallycounterpoised in its fibrous texture for it has substantially the sameelasticity, rigidity and tensile strength in all directions on itssurface and unmounted is substantially uniformly sensitive at all ointsof its surface. Such a sounding boardD would not, however, in itself berigid enough to support the pressure of the high tension strings againstthe bridges.

Such a predominant low partial tone sounding board when made of woodsuch as spruce would not, however, have in itself suffcient rigidity andresistance to support the pressure of high-tension strings against thebridge, and requires a support which will not, first, interfere with theproper and symmetrical segmentation of the board as do the ribshereinabove referred to and, second, which will not so decrease thesensitiveness of the board to the large segmentation as to produce apredominant overtone board. I have overcome these difficulties, byproviding for. such a board what I shall term a vibrating support.

In the preferred embodiment of my invention, I employ such a predominantlow parv` tial tone board .in combination with a support consisting of asecondary sounding board 9 spaced from the primary board and connectedthereto preferably by a plurality of suitably-disposed sound posts 10.11 and 12.

I connect this secondary sounding board to the primary sounding board bysuch sound posts preferably at a plurality of points just below thebridges and between the same and the edge of the sounding board, two ormore of such sound posts preferably being employed, as shown, adjacentto the long bridge 13 and one adjacent to the short bass bridge :Ihestring-plate 15 may be mounted in the .conventional manner at one sideof the primary board and the strings 16 extend across the bridges 13 and14 in the usual way to--`cajuse vibratlons of the strings to betransmitted to the sounding board, any suitable means being employed tovibrate the strings.

The positions of the sound posts 10, 11 and 12 as hereinabovedescribednot only supports the )rimary board and enables it to withstan the highpressure of the strings, but causes any vibrations transmitted by astring through the bridge of the primary sounding board to becommunicated -by the sound posts to the secondary board 9 which, asshown, is mounted at the outer side of marginal boards 17, 18, 19 and 20which form a frame therefor and are preferably provided with a depressedseat 21 for the said board which, as shown, is secured at its marginaledges to its seat by strips 22 and screws 23 but may be so secured inany suitable manner. en so arranged, it completely closes the back ofthe piano and is spaced somewhat from the intermediate posts 4, 5 and 6to permit free vibration intermediate its edges.

The transmission of vibrations to said secondary board 9 greatlyenlarges the vibrating surface and increases the volume of soundproduced by the piano, and the novel positions of such posts cause thatportion of the sounding board 1 extending from the bridge to itsattachment with the frame together with a post to act, in thetransmission of such vibrations to the secondary sounding-board, asacomposite leverwith power exerted on the portion of the primarysounding-board 1 to which the bridge is connected, the fulcrum of thesaid composite lever bein at the point of attachment of the soundingoardwith the frame.

The secondary sounding board 9, which also is a predominant fundamentalsounding board of similar homogeneous text-ure is preferably leftuncrowned and is arranged to cause a return or responsiveresilientpressure through the sound posts to the primary board 1. Inthis way, any vibration' of the strings will be communicated throuvh thebridge to the primary sounding boardb 1, and in communicating thisvibration to the secondary board, the primary board will, as aforesaidbecause of such positions of the sound posts, the portion of thesounding board 1 extending from the bridge to theattachment of the saidsounding-board with the frame together with a post will act as acomposite lever with power exerted on the portion of said primary boardto which t-he bridge is connected. the fulcrum of the composite` leverbeing at the point of attachment of the said primary sounding-board tothe frame and the said vibrations will thus be transmitted to theresilient or vibrating secondary sounding board which is in turnvibrated. Because of its elasticity, the secondary sounding-board givesa counter-impulse 0r opposite impulse and thereb not only causes aquicker recovery of tl'ie primary sounding board from the impulse of anyparticular vibration of a string, but causes an accelerated swing orvibration in the opposite direction, thus increasing the amplitude ofvibration of thc boards and the volume of sound produced thereby.

The employment of a secondary sounding board suitably spaced as aboveset forth from the primary sounding board also forms intermediate suchprimary sounding board and the seconda sounding board a resonance cavity24 which further reinforces lthe tones which are produced by theprim-ary and secondary sounding boards at the adjacent sides of suchboards. To procure the most effective use of the resonance cavity soprovided, I preferably have the spaces between the two boards completelyenclosed except at the top of the piano which is left open to permit thedischarge of the reinforced air waves therefrom. I also preferably shapethe said cavity as far as possible to concentrate the sound Wavesproduced in such cavity near a restricted outlet 25. For this purpose ofconcentrating air waves near the outlet, I provide each corner of thebottomy of the piano with a block 26 having its inner surface 27 or 28which forms the boundary of the cavity curved from end to end. Theseblocks 26 ill in and round out the lower corners and such blocks, aswell as side edges of the cavity, are preferably provided with adepressed groove 29 of semi-circular cross-section for the purpose offurther concentrating air waves.' The `side walls of the cavityintermediate the outlet and the lower end thereof are also preferablyprovided with blocks 30, 31, 32 and 33 having curved inwardly extendingfaces which project into the cavity, and are adapted to restrict theoutlet and further concentrate contiguous to the outlet the air wavesissuing therefrom. The intermediate posts which extend through thecavity 24 are preferably rounded' off at their corners, as shown in Fig.4, so as to kpresent as little interference as possible to thereinforcement, conducting and concentration of sound waves by the saidresonance cavity and the square inner tops of the corner posts are alsopreferably rounded otf as shown at 24 in Fig. 3. The intermediate postsare, as aforesaid, disposed centrally in the cavity and without touchingeither of the two sound boards on opposite sides thereof so that thesound waves produced in the cavity. are reinforced and concentrated andthen discharged upwardly between the intermediate posts and between suchintermediate posts and the end posts, an outlet 0r opening'25 beingprovided for this purpose. This out-let is preferably provided with asuitable cover 34 which may be hinged at its rear end, as shown, andpreferably has a sound channel 35 to enable the conduction ot' soundwaves to the front of the piano. I also preferably provide in this coverat the front edge thcreo't', a. series of discharge openings 36 topermit the discharge of air waves from the cavity therethrough when thecover is iu closed position.

.In Figs. 7 and R, I have shown a slightly modified form of soundingboard in which the sensitiveness oi the primary sounding board isincreased at the corner thereof on which the high treble strings aremounted by providing slots S7 and also by raising the end of the bridge38 which supports the high treble strings and raising and thinning thesame progressively toward the higher tones, thus enabling the highesttones to have the benefit of the. greatest leverage of the bridge in thetransmission of their vibrations to the sounding board l and stillbalancing the gradually reduced pressure of the strings.

Having described my invention, I claim:

l. A sounding board for pianos having a ribless rear surface and of athinness and rigidity to segment for the reproduction of composite toneshaving a predominance of low partial tones, a support. for the edges ofsaid board, an additional elastic support arranged at the rear of saidboard and means for connecting said support and board distant Jfrom theedges thereof.

2. A sounding board for pianos of substantially counterpoised texturehaving a substantially smooth and ribless rear surface and of a thinnessand rigidity to segment for the reproduction of composite tones having apredominance of low partial tones, a support for the edges of saidboard, an additional elastic support arranged at the rear of said hoardand means for connecting said support and board distant from the edgesthereof.

3. A sounding board for pianos of substantially homogeneous texture,having a substantially smooth and ribless rear surface and composed of aplurality of superposed layers of Wood, said board being of a thinnessand rigidity to segment for the reproduction of composite tones having apredominance oit low partial tones, a support for the edges of saidboard, an additional elastic support arranged at the rear of said boardand means for connecting said support and board distant from the edgesthereof.

4. A sounding board for pianos of substantially counterpoised textureand having a substantially smooth and ribless rear surface and composedof superposed layers of Wood having the grains of suoli layers crossingeach other, said board being of a thinness and rigidity to segment forthe reproduction of composite tones having a predominance of low partialtones, a support for the edges of said board, an additional elasticsupport arranged at the rear of said board and means for connecting saidsupport and board distant from the edges thereof.

5. In a piano, the combination with strings and means for supporting andvibrating the same, of a sounding board of substantially counterpoisedtexture and having a substantially smooth and ribless rear surface,comprising superposed layers of Wood having the grains of such layerscrossing each other, said board being of a thinness and rigidity tosegment for the reproduction of composite tones having a predominance oflow partial tones, means for transmittinfv the vibrations of thestrinfrs to the boar suitable means for supporting said board at itsedges, an additional elastic support arranged at the rear of said boardand a lurality of posts connecting said rear sur ace between the edgesof said board with said elastic support.

6. In a piano, the combination with strings and means for supporting andvibrating the saine, of a sounding board having a substantially smooth,ribless rear surface secured at its marginal edges, said sounding boardbeing of a thinness and rigidity' to segment for the reproduction ofcomposite tones having a predominance of low partial tones, means fortransmitting the vibrations of the strings to the said sounding board,means for supporting said board at its edges, an additional elasticsupport arranged at the rear of said board and a lurality of postsconnect-ing said rear sur ace between the edges of said board with saidelastic support.

7. In a piano, the combination with strings and means for supporting andvibrating the same, of a primary sounding board comprising a soundingboard having a substantially smooth and ribless rear surface and of athinness and rigidity to segment for the reproduction of composite toneshaving a predominance of low partial tones; means for transmitting thevibrations of the strings to the said sounding board; means forsupporting said primary sounding board at its edges, an elastic secondarsounding board independently supporte at the rear of said primary boardand spaced therefrom and sound posts connecting said secondary soundingboard and said primary sounding board to support the latter.

8. In a piano, the combination with strings and means for supporting andvibrating the same, of a primary sounding board comprising a soundingboard having a substantially smooth and ribless rear surface and of athinness and rigidity to segment for the reproduction of composite toneshaving a predominance of low partial tones; a bridge for transmittingthe vibrations of the strings to the said sounding board; means forsupporting said primary sounding board at its edges, an elasticsecondary sounding board independently supported at the rear of saidprimary u board and spaced therefrom, and sound posts connecting saidsecondary sounding board and said primary sounding board to support thelatter, said posts being ositioned adja cent to the bridge at the si ethereof opposite to the vibrated portion of the strings.

9. In a piano, the combination with strings and means for supportin andvibrating the same, of a rimary soun ing board having a substantial ysmooth and ribless rear surface,

and of a thinness and rigidity to segment for the reproduction ofcomposite tones having a predominance of low vpartial tones; means fortransmitting the vibrations of the strings to the said primary soundingboard, means for suitably supporting said primary board; an elasticsecondary sounding board independently supported at the rear of saidprima-ry soun ing board and arranged to form a closure for the rear ofthe piano spaced from the primary sounding board to provide a resonancecavity between such primary sounding board and said closure; said cavityhaving walls shaped to concentrate air waves near an outlet at one endthereof and sound posts arranged between the edges of said primary andsecondary boards.

10. In a piano the combination with strin and means for supporting andvibrating t e same, of a primary sounding board of substantiallycounterpoised texture and composed of superposed layers with the graincrossing, said primary soundin board having a substantially smoothA anribless rear surface and being of a thinness and rigidity to segment forthe reproduction of composite tones having a predominance of low partialtones; means for transmitting the vibrations of the strin to the saidsounding board, means for suitably supportin said board; an elasticseconda sounding oard independentl supporte at the rear ofsaid primarysoun in board and arranged to form a closure for t e rear of the pianospaced from the primary sounding board to provide a resonance cavitybetween such primary sounding board and closure, said cavity havingwalls shaped to concentrate air waves near a restricted outlet at thetop thereof, and sound posts arranged between the edges of said pri--mary and secondary boards.

11. In a piano, thecombinationwithst and means for supporting andvibrating t e same, of a primary sounding board of substantiallycounterpoised texture and having a substantially smooth and ribless rearsurface and of a thinness and rigidity to segment for the reproductionof composite tones having a predominance of low artial'tones; means fortransmitting the vi rations of the strings to the board, means forsuitably supporting said board at its edges; an elastic secondarysounding board independentl supported at the rear of said primarysounding board and being of substantially homogeneous texture and of athinnessand rigidity adapted to segment favorably for the reproductionof composite tones having a predominance of low partial tones, saidsecondary board being arranged to close the rear of the piano to providea resonance cavity between such primary sounding board and suchsecondary board and sound posts between said primary and secondaryboards for vibratably supporting said rimary sounding board between itsedges an transmitting vibrations between the two boards.

12. In a piano the combination with strin and means for supporting andvibrating t e same, of a primary soundin board composed of superposedcross-graine layers and of a substantially counterpoised texture andhaving a substantially smooth and ribless 'rear surface and being of athinness and rigidity to segment for the reproduction of composite toneshaving a predominance of low partial tones; means for transmittin thevibrations of the strings to the boar means for suitably supporting saidboard at its edges, means for supporting said primary sounding boardintermediate its edges and spaced therefrom, comprisin an elesaticsecondary sounding board independently7 supported at the rear of saidprimary soun ing board and composed of superposed crossgrained layersand of substantial] neous texture and of a thinness an rigidity adaptedto segment favorably for the reproduction of composite tones having apredominance of low partial tones and sound posts suitably disposedintermediate said primary and secondary boards.

In witness whereof, I have signed my name nto the foregoingspecification.

FLOYD s. MUCKEY.

homo-

